1993 Regal 3800 Exhaust Options

['93RegalGS3800]

Awhile ago I fixed the wiring harness from rodent damage and installed a new intake manifold. in the midst of installing the intake I left one important part out of the equation...The PCV valve. Car smoked like a MF-er and the exhaust might as well been the equivalent of a fog machine on steroids. Ended up clogging the cateletic converter (BLAH ). Now it's totally shot and I'm wondering if I should just delete it. Lets be honest...Cats are damaged by crap that happens upstream in the engine. This is the second one that the car is on and I wanna not have to fool with putting another one in when it would be cheaper just to get a piece of pipe to delete it with. Thing is that if I delete the cat then thanks to the computer the engine will be running in this weird thing called "open loop" all the time causing it to run rich. Is there any way I can fool the computer into thinking that the cat still exists?

 

I'd rather not fool with excessive aftermarket stuff. My car is OEM spec and I don't really want to tamper with it too much. I'd prefer to keep it as close as it was when it came off the assembly line. If there is a reliable way to delete the cat without any extreme aftermarket stuff then that would be easier for me to do. If I ever mod a W then I'll get another and do that pipe dream RWD conversion I've always wanted to do.

 

With that in consideration I'm open to any and all advise and suggestions.

[nitehawkjcb]

Want to keep it OEM? Put another cat on it.

 

You could delete the cat and put an O2 simulator in there (if you can find one). As long as you have one O2 sensor (on the manifold) you should be good.

 

You'll need a cat to pass emissions though, most likely.

[Imp558]

If there's no sniffer test in your area you can remove the cat and hollow it out. Only need an O2 sim on a newer car with a rear O2. It'll smell like a '70's car a bit but not bad.

['93RegalGS3800]

Want to keep it OEM? Put another cat on it.

 

You could delete the cat and put an O2 simulator in there (if you can find one). As long as you have one O2 sensor (on the manifold) you should be good.

 

You'll need a cat to pass emissions though, most likely.

 

Emissions test? Whats that? I live in Florida and have never heard of such a thing! LOL!

O2 simulator eh? I may have to look into that.

Also thats a sweet Monte in your sig pic. Never seen a cowl on a W before. I like it.

['93RegalGS3800]

If there's no sniffer test in your area you can remove the cat and hollow it out. Only need an O2 sim on a newer car with a rear O2. It'll smell like a '70's car a bit but not bad.

 

I thought about hollowing it out and rigging something inside the hollowed cat to fool O2. Do these cars even have a rear O2? last time I was under the car I did not notice anything "poking into" the exhaust like an O2 would. I know my '86 Camaro parts bin had a rear O2 on the Y-pipe. Guess I'll find that out once I drop the exhaust.

[RobertISaar]

a 93 3800 doesn't have a rear(cat sensor) O2, only the one mounted in the rear manifold.

 

if you pull that, the ECM will go open loop, set DTCs and in general not be very happy.

 

cat? it doesn't care if it exists or not.

['93RegalGS3800]

a 93 3800 doesn't have a rear(cat sensor) O2, only the one mounted in the rear manifold.

 

if you pull that, the ECM will go open loop, set DTCs and in general not be very happy.

 

cat? it doesn't care if it exists or not.

 

I'm wondering what effect I'll get if the converter is removed. I want to assume the rear O2 on the manifold will hate me and send a bad reading to the PCM causing the engine to run in open loop.

 

Arg. This is why pre '80's cars are sought after. This computer crap is just too complicated to modify.

[RobertISaar]

cat? it doesn't care if it exists or not.

 

i already told you exactly what would happen. the PCM doesn't know if the cat exists or not, the only O2 sensor isn't in any way effected by its presence or absence.

 

this "computer crap" is what i do. with what used to take a lot of time spent under the hood guessing what the engine wants, i can instead spend a couple of minutes changing things with my keyboard. i would be happy if i never touched a carb again.

[94 olds vert]

I dunno. I still love carbs. I used to spend a lot of time getting the carbs on the Corvair just perfect. Iys a chore when you have 4 of them.

 

Remove the CAT replace with straight pipe or better yet a glasspack. What sound do you want out of your 3800?

 

You a pretty limited, but quite is better on a 3800.

[RobertISaar]

Iys a chore when you have 4 of them.

 

you have nightmares about a 4 guage manifold vacuum setup for sync'ing the carbs? even with proper tools, they're a pain and only ever work correctly at one temperature and elevation. then you have the feedback carbs, which kind of get around that issue, but if you have to introduce one of those, you might as well go TBI.

[nitehawkjcb]

Emissions test? Whats that? I live in Florida and have never heard of such a thing! LOL!

O2 simulator eh? I may have to look into that.

Also thats a sweet Monte in your sig pic. Never seen a cowl on a W before. I like it.

 

lol must be nice! I'd love to not have to get my car inspected.

 

Thanks a lot man, I've put a lot of time and hard work into it, that's for sure.

['93RegalGS3800]

i already told you exactly what would happen. the PCM doesn't know if the cat exists or not, the only O2 sensor isn't in any way effected by its presence or absence.

 

this "computer crap" is what i do. with what used to take a lot of time spent under the hood guessing what the engine wants, i can instead spend a couple of minutes changing things with my keyboard. i would be happy if i never touched a carb again.

 

Oh. I did not catch that the first time around. I must be dumb.

 

I'll be honest about not being a fan of computer controls in cars. It's not my personal preference. Seems like you'd have a better time trying to adjust your second stage than fooling with fixing some silly glitch in the wiring itself. While plugging in a scan tool gives you information on different systems and whatnot I find myself attracted to the simplicity of old school engines. I like not having to surround my car in fox piss to keep the rodents out of my wiring. I had to fix some major wiring damage as explained in the origional post and if it weren't for my Dad being there with his 35+ years in the mechanic industry I would have had no idea WTF I was doing.

['93RegalGS3800]

I dunno. I still love carbs. I used to spend a lot of time getting the carbs on the Corvair just perfect. Iys a chore when you have 4 of them.

 

Remove the CAT replace with straight pipe or better yet a glasspack. What sound do you want out of your 3800?

 

You a pretty limited, but quite is better on a 3800.

 

I'm not trying to be the loudest car on the block. I think at the most I'd just do a converter delete and let the rest of the exhaust system do it's thing. While it's an interesting idea to go ahead and install an aftermarket setup I'm really trying to keep this car OEM. I've invested a lot of emotional value in it over the years and find myself satisfied with how it stands.

 

Won't deleting the cat make the car a bit louder? I know I'll gain some minuscule amount of horsepower with it removed. I was on another thread where 3800 exhaust notes have been brought up and apparently they don't sound the best when they are opened up. Guess I'm trying to go for a note similar to how it sounds with the stock setup. A little rumble would be nice and it had a little bit of rumble before the converter clogged. It wasn't necessarily noticeable or loud but I liked it.

['93RegalGS3800]

you have nightmares about a 4 guage manifold vacuum setup for sync'ing the carbs? even with proper tools, they're a pain and only ever work correctly at one temperature and elevation. then you have the feedback carbs, which kind of get around that issue, but if you have to introduce one of those, you might as well go TBI.

 

Ah... now i understand your preference. I'll admit that mechanical systems need mechanical adjustments. The electronic systems adjust on the fly and makes adjustments easier.

[RobertISaar]

I'm not trying to be the loudest car on the block. I think at the most I'd just do a converter delete and let the rest of the exhaust system do it's thing. While it's an interesting idea to go ahead and install an aftermarket setup I'm really trying to keep this car OEM. I've invested a lot of emotional value in it over the years and find myself satisfied with how it stands.

 

Won't deleting the cat make the car a bit louder? I know I'll gain some minuscule amount of horsepower with it removed. I was on another thread where 3800 exhaust notes have been brought up and apparently they don't sound the best when they are opened up. Guess I'm trying to go for a note similar to how it sounds with the stock setup. A little rumble would be nice and it had a little bit of rumble before the converter clogged. It wasn't necessarily noticeable or loud but I liked it.

 

you'll want to be careful if you do remove/blast through the cat.... it does absorb a pretty significant amount of sound on its own. if the cat is clogged/clogging, you'll certainly notice a difference from where you are now. where it was? maybe.

['93RegalGS3800]

More like where it was. It's totally clogged right now. It takes a moment before the car will even creep forward.

 

I'm gonna assume that with the converter removed that it will sound like a 60's car. They were audible with the equipment they had. I've never heard a W with catless exhaust. I just hope it's not too loud and doesn't sound like crap.